/Engine/Source/Editor/ContentBrowserData/Public/ContentBrowserDataSubsystem.h
The compiled filter is only valid until the data source changes, so only keep it for a short time (typically within a function call, or 1-frame).
void CompileFilter ( const [FName](API\Runtime\Core\UObject\FName) InPath, const [FContentBrowserDataFilter](API\Editor\ContentBrowserData\FContentBrowserDataFilter) & InFilter, [FContentBrowserDataCompiledFilter](API\Editor\ContentBrowserData\FContentBrowserDataCompiledFilte-) & OutCompiledFilter ) const